British Rail Class 231

The British Rail Class 231 is a class of eleven diesel-electric multiple units of the FLIRT family, which have been built for Transport for Wales by Swiss rolling stock manufacturer Stadler Rail. The first units entered service on 18 January 2023.

History
The previous Wales & Borders rail franchise operator, KeolisAmey Wales ordered the new trains. Although KeolisAmey was removed as the franchise operator and replaced by an operator of last resort Transport for Wales Rail, owned by the Welsh Government, the scheduled full fleet replacement continued.

The units began testing in Switzerland in July 2021 and in November 2021 the first two units were delivered to Cardiff Canton depot.

Transport for Wales
The Class 231 units are currently operating services on the Rhymney line, though it is expected they will operate services between and, and between /Newport and Ebbw Vale Town.

The official revenue launch of the Class 231 took place on 29 March 2023 at Caerphilly.

Technical details
Class 231 units have four passenger vehicles, along with a separate "Power Pack" vehicle at the centre of the unit that contains four diesel generator sets. The diesel generators comply with EU Stage V emissions regulations. All vehicles are linked by unpowered Jacobs bogies, while the outermost bogie at each end of each unit carries the traction motors.

Named units

 * Unit 231001 is named Sultan. It was suggested by a local school as part of a competition run by TfW, and is named after a statue at Ystrad Mynach of the pit ponies used in the local coal mines.